glcpp: Rename "errors" to "info_log."

Eventually, we'll want to be be able to print out warnings as well.
diff --git a/glcpp/glcpp.h b/glcpp/glcpp.h
index 4a2489a..e67469b 100644
--- a/glcpp/glcpp.h
+++ b/glcpp/glcpp.h
@@ -154,7 +154,7 @@
 	token_list_t *lex_from_list;
 	token_node_t *lex_from_node;
 	char *output;
-	char *errors;
+	char *info_log;
 };
 
 glcpp_parser_t *